Chapter D Flashcards
When sizing gas piping systems, what is considered low pressure?
0.5 psig / 3.5 kPa is considered low pressure. Note: Although 2psig is high pressure, the fittings are included in the tables. 5psig and higher the fittings are not included and must be calculated in using the fitting tables in the codebook.
1 kilowatt is how many BTU’s?
3412 BTU’s.
1 cubic meter is how many cubic feet?
35.31 cubic feet.
Are 2 psig gas pressures allowed inside one and two family dwellings?
Yes. The regulations also allow a 1.5 psig pressure drop, which allows increased gas flow.
System pressure - Pressure drop = ?
Inlet pressure. (Ex. System Pressure of 2 psig - Pressure Drop of 1.5 psig = 0.5 psig Inlet Pressure.
When sizing a gas piping system, is it more advisable to size the low pressure zone first or the high pressure zone?
The low pressure zone.
When sizing a gas piping system, when do you include fittings?
When sizing systems 5 psig or greater include fittings. (Note: When reading the header of the gas sizing tables in the code book, it tells you whether or not you need to add fittings.)
When including fittings in a high pressure gas piping system, do you include fittings which do not change the direction of the flow?
No, do not include fittings which do not change the direction of flow. (Tees on the run, pipe couplings, unions, reducing couplings, etc.)
How are propane cylinders sized?
They are sized by the pounds of propane they can store. For example: a “100 pound cylinder” can store 100 pounds of propane.
What is the range of sizes for propane cylinders?
1 pound to 500 pounds.
How are propane tanks sized?
Propane tanks are sized by the gallons of water they can hold. These are expressed as gallons of water capacity “w.c.” For example: A “1000 gallon w.c.” tank can hold 1000 gallons of water.
What is the range of sizes for propane tanks?
As small as 10 for gallons for motors, and up to 1000 gallons for residential and commercial use.
Where is the design information located on cylinders?
On the neck ring of each cylinder are design markings and specifications.
Where is the design information located on tanks?
The design information on tanks are stamped on a data plate and then attached to the tank.
What are the three valves commonly used on cylinders and tanks?
The service, filler and safety valves.
What are prestolite (POL) fittings used for?
Prestolite fittings are only used for vapor service connections.
Are independant filler valves used on stationary cylinders or portable cylinders?
Stationary cylinders. Portable cylinders do not use independant filler valves because they’re filled through the service valve at the plant.
What is the most common type of filler valve?
The double-back check valve is the most common.
What is the purpose of a safety relief valve on a LP-gas container?
To automatically relieve excess pressure that can build up inside a cylinder or a tank. If this valve cannot perform properly the cylinder or tank may rupture.
What is the pressure relief valve setting for cylinders?
375 psig.
What is the pressure relief valve setting for tanks?
312 or 250 psig.
When a fixed liquid level gauge emits a white fog or mist, what does this indicate?
This indicates that the maximum filling capacity has been reached and the filling operation must stopped.
What must a stationary cylinder or tank contain?
A filler valve, a safety relief valve, a service valve, and a fixed liquid level gauge.
Is LP-gas stored as a liquid or a vapor?
It’s stored as a liquid.
What’s the maximum percentage a LP-gas container can be filled?
80%.
What four things are necessary for corrosion to occur?
An anode, a cathode, an electrolyte, and a conductive path.
What’s another name for anodes and cathodes?
Electrodes.
What are the three methods of protecting underground piping from corrosion?
Protective coatings, electrical insulation, and cathodic protection.
What must a good protective coating have?
A high dialectric rating.
What test may be performed to check the quality of protective coatings?
The Jeep Test.
List four types of approved electrical insulation fittings:
Insulated couplings, insulated unions, insulated flanges, and insulated meter spuds.
What corrodes: anodes or cathodes?
Anodes corrode, cathodes don’t.
What are two methods of providing cathodic protection?
Sacrificial anodes. and impressed current.
When is impressed current used as a cathodic protection?
For large installations, involving several km of piping.
Should sacrificial anodes be installed above or below the pipe it’s protecting?
Below the pipe.
What are sacrificial anodes constructed of?
Magnesium.
How many feet / meters should a sacrificial anode be installed below a pipe?
3 feet / 1 meter.
How many feet / meters should a sacrificial anode be installed horizontally to the pipe?
2 feet / 0.6 meters.
